Shoes equipped with spikes are used for getting a good grip on slippery surfaces. Typically, spiked shoes are useful for people walking on streets or pavements covered with snow and ice and for golfers. Conventional spiked shoes suffer from the drawback that the spikes are in constant contact with ground surface during wear, also in situations where spikes are not necessary, such as on hard surfaces, or where spikes are unsuitable, such as on most indoor floors. This causes excessive wear on the spikes and certain surfaces or makes a frequent switching of shoes necessary.
To overcome these disadvantages various examples of shoes with retractable spikes has been proposed over the years. U.S. Pat. No. 4,873,774 discloses one example where a fluid pressure is used to push cleats to extend from the sole bottom. Another example is disclosed in U.S. Pat. No. 5,299,369 where pneumatically actuated, rotatable spikes are used. Still another example is disclosed in U.S. Pat. No. 6,058,627 where spikes are slidable between a retracted and an extended position. Still another example is disclosed in U.S. Pat. No. 6,125,556 where high pressure liquid is used to extend the spikes. None of the various examples of shoes with retractable spikes appears to have been any success; possibly because of a too complex structure, a too low structural strength or of functioning problems when exposed to dirt. SE524692 discloses another approach where hydraulic lifting pads placed under the outer sole are arranged to expand such that spikes mounted to the outer sole loose contact with the ground. Also this construction is relatively complex involving hydraulic conduits and controlling devices.